Covering a region that extends into both the Clearwater National Forest and Bitterroot National Forest, the Selway-Bitterroot Wilderness covers more than 1.2 million acres of North Central Region. Mechanized equipment, including bicycles, are not permitted in the wilderness or on trails leading into the wilderness, so travel is limited to such means as horseback, boat, or foot. Over 600 miles of trails are maintained in the wilderness, which was one of the first to be created under the Wilderness Act of 1964.